/**
 * @Author: YCKOKO
 * @Date: ${YEAR}-${MONTH}-${DAY}
 * @Time:${HOUR}:${MINUTE}
 * @Description:
 */
public class Main {


    public static void main(String[] args) {
        String str = "MCMXCIV";
        int ret = romanToInt(str);
        System.out.println(ret);
    }

    public static int romanToInt(String s) {
        int result = 0;
        int prenum = getValue(s.charAt(0));
        for(int i = 1; i < s.length(); i++){
            int num = getValue(s.charAt(i));
            if(prenum < num ){
                result -= prenum;
            }else{
                result += prenum;
            }
            prenum = num;
        }
        result += prenum;
        return result;
    }


    private static int getValue(char ch){
        switch(ch){
            case 'I': return 1;
            case 'V': return 5;
            case 'X': return 10;
            case 'L': return 50;
            case 'C': return 100;
            case 'D': return 500;
            case 'M': return 1000;
            default: return 0;
        }
    }
}